Track structure for drawout switchgear apparatus



Dec. 9, 1969 FQ L ET AL 3,483,338

TRACK 'STRUCTURE FOR DRAWOUT SWITCHGEAR APPARATUS Filed Nov. 27, 1968 3 Sheets-Sheet 1 (Q2 .LQ

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INVENTORS Fred Bould and Nogor J. Porel Mama/4a..

AT TOR NEY Dec. 9, 1969 BQULD ET AL TRACK STRUCTURE FOR DRAWOUT SWITCHGEAR APPARATUS Filed Nov. 27. 1968 3 Sheets-Sheet 2 Hlllll NQE Dec. 9, 1969 F BOULD ET AL 3,483,338

TRACK STRUCTURE FOR DRAWOUT SWITCHGEAR APPARATUS Filed Nov. 27, 1968 5 Sheets-Sheet :5

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United States Patent. F

3,483,338 TRACK STRUCTURE FOR DRAWOUT SWITCHGEAR APPARATUS Fred Bould, Pittsburgh, and N agar J. Patel, East McKeesport, Pa., assignors to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Nov. 27, 1968, Ser. No. 779,505 Int. Cl. H01h 9/20, 33/46 US. Cl. 200-50 8 Claims ABSTRACT OF THE DISCLOSURE A switchgear apparatus comprising an apparatus unit or circuit breaker which is removably disposed in a cell or housing and which is supported on a stationary track when the unit is in the cell and on an extensible track when the unit is moved out of the cell.

CROSS REFERENCES TO RELATED APPLICATIONS BACKGROUND OF THE INVENTION This invention relates to switchgear apparatus and more particularly to switchgear of the drawout type. When a circuit breaker or similar apparatus of the horizontal drawout type is mounted in a cell or housing, it has been the practice to provide a track structure which permits the switchgear apparatus unit to be rolled or moved out of the housing or cubicle to a position in which the unit is readily available for inspection or maintenance. Known track structures of this general type are disclosed in US. Patents 2,264,755, 2,295,405, 2,412,931, 2,443,669 and 2,921,998. These known track structures have certain disadvantages with respect to the relative size of the parts of the track structures or with respect to the structural loading of certain parts of the track structure in certain operating positions of the overall switchgear apparatus.

SUMMARY OF THE INVENTION In accordance with the invention the extensible portion of a retractable track structure is slidably supported on an associated stationary track for movement between an extended position and a retracted position by a pair of pins which are mounted on the stationary track and which pass through a longitudinal slot in the extensible track portion. The pins are positioned to support the extensible track portion at an acute angle with respect to the stationary track until the extensible track is moved to the extended position. In the extended position, one end of the slot in the extensible track portion includes a transverse portion which permits the extensible track to pivotally move about one of the pins into alignment with the stationary track. In certain embodiments, two stationary tracks on opposite sides of a movable circuit breaker may be incorporated into a generally U-shaped supporting member.

It is therefore an object of this invention to provide an improved track structure for switchgear apparatus of the drawout type.

3,483,338 Patented Dec. 9, 1969 BRIEF DESCRIPTION OF THE DRAWINGS Other objects of the invention will be apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a view in front elevation of switchgear apparatus embodying our invention, a portion being broken away for clearness;

FIG. 2 is a view in side elevation of the structure shown in FIG. 1 and illustrating a removable unit fully inserted into an associated cubicle or cell;

FIG. 3 is an enlarged view, partly in section and partly in front elevation, taken along the line IIIIII of FIG. 2, of a portion of the structure shown in FIG. 2;

FIG. 4 is a view similar to FIG. 2 but with the door or cubicle removed and the removable unit withdrawn from its operating position inside the associated cubicle;

FIG. 5 is an enlarged view, in side elevation, of an extensible track which forms part of the structure shown in FIGS. 1 through 4; and

FIG. 6 is an enlarged View, in plane, or a portion of the extensible track shown in FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings and FIGS. 1 and 2 in particular, the switchgear apparatus shown therein comprises a removable switchgear unit 20 which may be a circuit breaker of the drawout type or other switching equipment, such as a network protector, which is mounted in a sheet-metal cubicle or cell 10 having a cover or door 12. The cell 10 is of the metal-enclosed type and includes the side members 14, the partition members 15 which divide the cell 10 from similar cells disposed above and below the one shown and a rear wall member 17 opposite the cover or door 12. The switchgear unit 20 may be provided with suitable upper and lower disconnecting contact assemblies 21 which are removably assembled on the upper and lower terminals of the switchgear unit 20 and which are adapted to engage the corresponding upper and lower fixed electrical conductors or studs 23 in order to electrically connect the switchgear unit 20 to the bus bars or electrical power conductors of the overall switchgear apparatus. Each of the disconnecting contact assemblies 21 may be of the type which is described in detail in copending application Ser. No. 538,996, filed Mar. 31, 1966, by I. D. Findley which is now issued as US. Patent 3,247,419, assigned to the same assignee as the present application.

In order to support the switchgear unit 20, the switchgear unit 20 is provided with a pair of spaced rollers or wheels 22 disposed on each side of the switchgear unit 20. The rollers 22 are grooved around their circumferences as shown in FIG. 3 and adapted to fit over the top edges or surfaces of the extensible track structure 40 which are disposed at the opposite sides of and within the housing or cell 10. The rollers 22 are pivotally supported on the studs or shafts 24 which project away from the opposite sides of a supporting frame which forms part of the switchgear unit 20, as best shown in FIGS. 2 and 3.

In order to simplify the description, only the track structure 40 at the right side of the cell 10, as viewed In FIG. 1, will be described in detail. It will be understood that the track structure 40 at the left side of the cell 10 is similar to the track structure 40- at the right side of the cell 10 which will be described in detail.

The extensible track structure 40 at the right side of the cell 10 comprises a stationary or fixed track portion 34 and an extensible track portion 44. As illustrated, the

stationary track portion 34 forms part of a generally U- shaped supporting member 30 which comprises a pair of upwardly projecting flange portions 32 and 34 which are spaced from one another and which are structurally interconnected by a connecting portion or bight portion 36, as best shown in FIG. 1. The flange portion 34 of the supporting member 30 forms the stationary track portion 34 at the right side of the cell 10, while the flange portion 32 of the supporting member 30 forms the stationary track portion 32 of the track structure 40 at the left side of the cell 10. The generally U-shaped supporting member 30 may be secured to and supported by the structural members which form part of the cell or housing such as the partition below the supporting member 30' by suitable means, such as welding or bolts. It is to be noted that when the switchgear unit is disposed inside the associated cell or housing 10 as best shown in FIGS. 1 and 2, the rollers '22 of the switchgear unit 20 are supported only on the top surface or edge of the stationary track portions 32 and 34 which form part of the supporting member and not on the extensible track portions 44 which form part of the track structures disposed at the opposite sides of the cell 10.

In order to slidably support the extensible track portion 44 which forms part of the track structure 40 at the right side of the cell 10 on the adjacent stationary track portion 34, a pair of pins 62 and 64 are mounted on the stationary track portion 34 and project laterally away from the stationary track portion 34 as best shown in FIGS. 2 and 3. As shown in FIG. 2, the pins 62 and 64 are spaced from one another along the length of the stationary track portion 34 and the pin 64 which is farther away from the door or cover 12 is spaced relatively farther away from the top edge or surface of the stationary track portion 34 than the pin 62 which is disposed relatively closer to the cover or door 12. In order to permit rectilinear sliding movement of the extensible track portion 44 with respect to the associated stationary track portion 34, the extensible track portion 44, as best shown in FIG. 5, includes a longitudinally extending slot 45 through which the supporting pins 62 and 64 pass as shown in FIG. 2. In order to retain the extensible track portions 44 in assembled relation with the associated stationary track portions 32 and 34, the supporting pins 62 and 64 may each include a flange portion, as indicated at 64A for the supporting pin 64 in FIG. 3, which is of a relatively larger size than the width of the slot 45. The extensible track portions 44 may also include the relatively larger openings as indicated at 46B in FIG. 5 to facilitate the assembly of the extensible track portions 44 with the associated stationary track portions 32 and 34 where desired in a particular application. As illustrated, a reinforcing member or shielding member 46 may besecured to each of the extensible track portions 44 and include an intermediate portion 46A which is spaced away from the extensible track portion 44 and the associated supporting pins 62 and 64. The reinforcing or shielding member 46 may be secured to the extensible track portion 44 by any suitable means, such as welding or bolts.

It is important to note that the extensible track portions 44 are supported on the associated stationary track portions 32 and 34 for sliding movement at an acute angle with respect to the associated stationary track portions 32 and 34 with the line of movement of the extensible track portions 44 being determined by the relative positions of the supporting pins 62 and 64 on the stationary track portions 32 and 34. It is also important to note that, as mentioned previously, when a switchgear unit 20 is disposed inside the associated cell 10, the supporting rollers 22 engage only the stationary track portions 32 and 34 and the extensible track portions 44 which are slidably supported on the stationary track portions do not carry any of the weight of the switchgear unit 20 when the switchgear unit 20 is disposed inside the associated cell 10. In other words, the upper or top edge 44A of each of the extensible track portions 44 and the top edge 46C of each of the reinforcing members 46 intersect the top edge or surface of the associated stationary track portions 32 and 34 in front of the rollers 22 which are disposed on the switchgear unit 20, as best shown in FIG. 2.

In order to permit pivotal movement of each of the extensible track portions 44 about the supporting pins 62 when the extensible track portions 44 are slidably actuated from the retracted positions shown in FIG. 2 to the extended position shown in FIG. 4, each of the slots 45 in the extensible track portions 44 includes a portion 45A at the inner end thereof which extends generally transversely or at a right angle with respect to the main portion of the longitudinal slot 44. When the extensible track portions or sections 44 are actuated to the extended positions as shown in FIG. 4, each of the extensible track portions 44 pivotally moves about the front supporting pin 62 until the rear supporting pin 64 is disposed in the slot portion 45A with the top surface or supporting surface 44A of each extensible track portion 44 being then actuated into substantial alignment with the top surface or edge of the associated stationary'track portion as shown for the track portion 34 in FIG. 4.

In order to prevent the switchgear unit 20 from rolling off the stationary track portions 32 and 34 when the switchgear unit 20 is inside the associated cell 10 and to prevent the switchgear unit 20 from rolling off the extensible track portion 44 when the switchgear unit 20 is moved out of the associated cell 10 as shown in FIG. 4, a stop member 48 is secured to the front end of each of the extensible track portions 44 by suitable means, such as Welding with the stop member 48 extending or projecting above the top edge or surface of the extensible track portion 44, as shown in FIGS. 2 and 4.

It is to be noted that a slotted cam member 29 is secured to each of the stationanry track portions 32 and 34 by suitable means, such as welding, and is adapted to cooperate with a roller 25 which is mounted on a crank arm 27 that forms part of a racking mechanism of the switchgear apparatus unit 20 for actuating the latter unit between certain operating positions.

In the operation of the track structures 40, when the switchgear unit 20 is normally disposed inside the associated cell or housing 10, the switchgear unit 20 is sup ported entirely by the stationary track portions 32 and 34, as previously mentioned, and the top surfaces of the extensible track portions 44 are not engaged by the rollers 22 on the switchgear unit 20', as shown in FIG. 2. In other words, the extensible track portions 44 are not mechanically or structurally loaded by the weight of the switchgear unit 20 when the switchgear unit 20 is disposed inside the associated cell or housing 10.

When it is desired to withdraw the switchgear unit 20 out of the cell or housing 10 for maintenance or inspection, the door 12 is first removed or actuated to a position at one side of the cell 10 as indicated in FIG. 1. Next, the extensible track portions 44 are slidably actuated from the retracted positions inside the cell 10 as shown in FIG. 2 through the extended positions shown in FIG. 4. As indicated previously, the extensible track portions 44 move at an acute angle with respect to the associated stationary track portions 32 and 34 until the extensible track portions 44 reach the fully extended positions indicated in FIG. 4 at which time the extensible track portions move pivotally into alignment with the associated stationary track portions 32 and 34. Pinally, the switchgear unit 20 may be actuated or rolled out of the cell or housing 10 to the withdrawn position shown in FIG. 4. In order to return the switchgear unit 20 from the withdrawn position shown in FIG. 4 to its normal position inside the cell or housing 10 shown in FIG. 2, the switchgear unit 20 is first rolled into the cell or housing 10 until the rollers 22 are supported only by the stationary track portions 32 and 34 as shown in FIG. 2. Next the extensible track portions 44 may be slidably actuated or pushed back into the retracted positions without the weight or load of the switchgear unit impeding the return of the extensible track portions to the positions shown in FIG. 2.

It is to be understood that in any particular application the stationary track portions 32 and 34 need not be combined or form part of a unitary U-shaped supporting member as disclosed but that each of the stationary track portions may be independently supported by the structural members which form part of the cubicle or cell 10. It is also to be understood that the extensible track portions 44 may be disposed outside of the generally U-shaped supporting member rather than inside as illustrated where a more compact construction is not required.

The apparatus embodying the teachings of the invention has several advantages. For example, the switchgear apparatus embodying the track structures as disclosed is extremely compact in construction and is uniquely adapted for use with a generally U-shaped supporting member as disclosed. In addition, the extensible track portions which form part of the overall track structures as disclosed may be readily actuated between an extended position and a retracted position without carrying the weight of the associated switchgear unit or being otherwise structurally loaded. Finally, the extensible track portions of the track structure as disclosed are not subject to carrying part or all of the weight of the associated switchgear unit when the switchgear unit is in normal operating position inside the associated cell or housing.

Since numerous changes may be made in the above described apparatus and different embodiments of the invention may be madewithout departing from the spirit and scope thereof, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

We claim as our invention:

1. A switchgear apparatus comprising a cell, a switchgear unit removably disposed in the cell and having rollers disposed thereon, a stationary track mounted in the cell and having a supporting surface which is engaged by said rollers when said unit is inside the cell to support said unit, and an extensible track having a supporting surface slidably supported on said stationary track for movement between a first position inside said cell and a second position in which said supporting surface of said extensible track projects outside of said cell to support said unit, only the supporting surface of said stationary track being engaged by said rollers when said extensible track is in said first position.

2. The combination as claimed in claim 1 wherein said extensible track includes a longitudinal slot and said stationary track has mounted thereon a pair of spaced pins which pass through said slot to slidably support said extensible track at an acute angle with respect to said stationary track in said first position, said slot including a transverse portion at one end to receive one of said pins in said second position of said extensible track to thereby permit said extensible track to pivotally move about the other of said pins into alignment with said stationary track.

3. The combination as claimed in claim 2 wherein said extensible track includes a projecting portion at one end to prevent said switchgear unit from moving 01f said extensible track in the second position thereof.

4. The combination as claimed in claim 2 wherein one of said pair of spaced pins is disposed relatively closer to the supporting surface of said stationary track and the other of said pair of spaced pins is disposed relatively farther away from the supporting surface of said station-- ary track.

5. The combination as claimed in claim 1 wherein an additional stationary track is mounted in said cell,

said stationary tracks being structurally joined by a connecting member to form a generally U- shaped unitary supporting member.

6. A switchgear apparatus comprising a cell, an apparatus unit removably disposed in the cell, a stationary track mounted in the cell for supporting said unit when said unit is inside the cell, a pair of spaced pins mounted on and projecting laterally from said stationary track, an extensible track having a longitudinal slot, said pair of pins passing through the slot of said extensible track to slidably support said extensible track for movement between a first retracted position and a second extended position said pins being positioned to support said extensible track at an acute angle with respect to said stationary track in the retracted position, said slot including a transverse portion at one end to permit said extensible track to pivotally move into substantially aligned relation with said stationary track in the extended position.

7. The combination as claimed in claim 6 wherein said apparatus unit has a plurality of rollers pivotally mounted thereon which engage only said stationary track in the retracted position of said extensible track.

8. The combination as claimed in claim 7 wherein one of said pair of spaced pins is disposed relatively closer to the rollers of said apparatus unit and the other of said pins is disposed relatively farther away from the rollers of said apparatus unit when said unit is inside said cell.

References Cited UNITED STATES PATENTS 2,264,755 12/1941 Johnson et al. 2,295,405 8/ 1942 Johnson et al. 2,412,931 12/ 1946 West. 2,762,878 9/1956 Wills. 2,851,549 9/1958 Keller et al. 3,297,839 1/1967 Fradley et al.

ROBERT K. SCHAEFER, Primary Examiner J. R. SCOTT, Assistant Examiner US. Cl. X.R. 

